SEATTLE NEWS ARCHIVES & FEATURES

What were the strange clouds over the Puget Sound area?

Aug 7, 2013, 9:24 AM | Updated: 9:49 am

These odd clouds observed over the Seattle-area late Tuesday were not from a jet contrail or aliens...

These odd clouds observed over the Seattle-area late Tuesday were not from a jet contrail or aliens. (Linda Thomas photo)

(Linda Thomas photo)

My guess was the strange pattern of clouds I saw over my house in Seattle late yesterday came from a scattered jet contrail.

It’s not a contrail, nor is it related to aliens.

The correct explanation comes from University of Washington Professor of Atmospheric Science, Cliff Mass.

“This a line of cirrus clouds that were precipitating ice crystals,” he explains. “These appendages with falling ice crystals are known as fall streaks or mare’s tails.”

Another weather expert, Jeff Schwartz, says they are a form of “Kelvin-Helmholtz waves, named after two 1800s researchers.”

A short science lesson – when two different layers of air are moving at different speeds in the atmosphere, a repeating wave or triangle structure will often form.

Enjoy another summer day!

By LINDA THOMAS

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What were the strange clouds over the Puget Sound area?